std: add a fixme to note performance issues in vec::from_elem.
trans::glue: don't allocate a pointer variable if it already exists

Removes one alloca and store from the drop glue of @ boxes. This speeds
up the rustc build by 1s (might be noise, though).
Add IterBytes impls for float/f32/f64. This allows creating
HashMaps with floats as keys.
trans::glue: don't generate struct destructors in the free glue

The free glue shouldn't be called for structs, and the drop glue already
contains the destructor.
Fix terminfo::param %i op
std: Remove doc references to reinterpret_cast
Remove the fuzzer

It is suffering from a bad case of megabitrot.
std: convert str::{map,levdistance,subslice_offset} to methods.

The first two become map_chars and lev_distance. Also, remove a few
allocations in rustdoc.
std: convert str::to_utf16 to a method.
std: simplify the string comparison implementations, using iterators.
std: continue improving the comparison trait impls for str.

This moves them all into the traits submodule, and delegates Ord
to the TotalOrd instance. It also deletes the stand-alone lt, gt,
ge and le functions.
std: test-fixes, remove warnings, syntax highlighting for code examples.
std: allow any sort of string to be Added with +.
rm vec::uniq_len
rm CopyableOrderedIter

replaced with OrdIterator
fix test
old_iter: rm the min/max free functions
remove unused imports
fix benchmark and the tutorials
auto merge of #7149 : thestinger/rust/vec, r=graydon